| The power transformer is one of the important equipment in the power system, the running stabilization and security plays a key role in the security of the power system. In the recent years, with the increase of the power capacity, transformer malfunction increases constantly, of which the rate caused by the close quarters or way out short-circuit remains high. This affects the power system safe running greatly. In order to prevent this kind of accident in advance, analysis and calculating the short circuit force of the power transformer in short circuit condition, conjoint analysis results, studying the weakness of the winding, reinforcing the winding themselves and the surrounding structures, improving the manufacturing technology and craft level will have a very important significance.In this thesis, the background and significance of this topic will be first described, then the research status at home and abroad of leakage magnetic field, the short-circuit force and the short-circuit strength of the power transformer will be discussed. Then the basic theory of the electromagnetic field and finite element calculation software will be introduced, while the magnetic leakage, short-circuit current, short circuit force causes and calculation method will be discussed. At last equivalent calculation model of the 63000kVA/110kV power transformer as an example will be set up in short-circuit situation based on finite element numerical calculation method. The leakage magnetic field of the windings, the short-circuit force will be calculated and analyzed and the short-circuit strength on the transformer model will be verified by using classic static calculation. The influencing factors of the power transformer short-circuit force will be proposed, and some conclusion for improving the short-circuit withstanding ability of the transformer with reference value for the designing and manufacturing departments will be obtained. |
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